Adjustable detector array for a nuclear medicine imaging system

ABSTRACT

Methods and systems are provided for a medical imaging system having a detector array. In one example, the detector array may include a plurality of adjustable imaging detectors, each of the plurality of adjustable imaging detectors including a detector unit, each detector unit having a plurality of rows of detector modules, wherein the plurality of adjustable imaging detectors may be arranged on an annular gantry, the annular gantry configured for rotation about an axis of a cylindrical aperture of the annular gantry, the axis extending a length of the cylindrical aperture, and wherein each of the plurality of adjustable imaging detectors may be disposed within the cylindrical aperture and may extend orthogonally toward the axis.

FIELD

Embodiments of the subject matter disclosed herein relate to medicalimaging systems, and more particularly to an adjustable detector arrayfor nuclear medicine imaging systems.

BACKGROUND

Nuclear medicine (NM) imaging systems may include multiple detectors ordetector heads for imaging a subject, such as a patient. For example,the detectors may be positioned adjacent to the subject on a gantry toacquire NM imaging data (e.g., radioactivity) with a wide field of view.The acquired NM imaging data may then be used to generate athree-dimensional (3D) image of the subject. Some NM imaging systems mayhave moving detector heads, such as gamma cameras, positioned to focuson a region of interest. One or more of the gamma cameras may be moved(for example, rotated) to different angular positions to acquire the NMimaging data. In one example, a detector array may include a pluralityof detectors dispersed around the gantry, which may each be moved (e.g.,translated and/or rotated) in close proximity to the subject to increasean imaging sensitivity. However, the close proximity may presentphysical (e.g., pinching) or mental (e.g., claustrophobia) discomfortfor the subject. Further, the imaging sensitivity may be fundamentallylimited by a specific configuration of cadmium zinc telluride (CZT)modules included in each detector. For example, each detector mayinclude a single row of CZT modules.

BRIEF DESCRIPTION

In one embodiment, a detector array may include a plurality ofadjustable imaging detectors, each of the plurality of adjustableimaging detectors including a detector unit, each detector unit having aplurality of rows of detector modules, wherein the plurality ofadjustable imaging detectors may be arranged on an annular gantry, theannular gantry configured for rotation about an axis of a cylindricalaperture of the annular gantry, the axis extending a length of thecylindrical aperture, and wherein each of the plurality of adjustableimaging detectors may be disposed within the cylindrical aperture andmay extend orthogonally toward the axis.

It should be understood that the brief description above is provided tointroduce in simplified form a selection of concepts that are furtherdescribed in the detailed description. It is not meant to identify keyor essential features of the claimed subject matter, the scope of whichis defined uniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood from reading thefollowing description of non-limiting embodiments, with reference to theattached drawings, wherein below:

FIG. 1 shows a schematic block diagram of a nuclear medicine (NM)imaging system, according to an embodiment;

FIG. 2 shows a schematic diagram of a detector unit for use in the NMimaging system, according to an embodiment;

FIG. 3 shows a schematic diagram illustrating various movements of animaging detector including the detector unit, according to anembodiment;

FIGS. 4A and 4B show schematic diagrams illustrating an exemplaryprocess for conforming a detector array of the NM imaging system to asubject to be imaged, according to an embodiment;

FIGS. 5A-5C show schematic diagrams illustrating a first exemplaryprocess for adjusting a position of the imaging detector including thedetector unit, according to an embodiment;

FIGS. 6A-6C show schematic diagrams illustrating a second exemplaryprocess for adjusting the position of the imaging detector including thedetector unit, according to an embodiment;

FIGS. 7A-7E show schematic diagrams illustrating exemplaryconfigurations of the detector array, according to an embodiment;

FIG. 8 shows a flow chart of a method for imaging a subject via the NMimaging system, according to an embodiment; and

FIG. 9 shows a flow chart of a method for positioning the detector arrayof the NM imaging system to image a subject, according to an embodiment.

DETAILED DESCRIPTION

The following description relates to various embodiments of nuclearmedicine (NM) imaging systems, and adjustable detector arrayconfigurations therefor. One example NM imaging system employing anexemplary detector array is depicted in FIG. 1. The detector array mayinclude a plurality of imaging detectors, each of the plurality ofimaging detectors including a respective detector unit having multiplerows of cadmium zinc telluride (CZT) modules, such as the detector unitdepicted in FIG. 2. Various configurations of the detector array havingvarying numbers of detector units are provided in FIGS. 7A-7E.

The detector unit may move around one axis of rotation and one pivotingaxis, and along one axis of translation, as depicted in FIG. 3, so as toconform to a subject to be imaged by the NM imaging system, an exemplaryprocess for which is depicted in FIGS. 4A and 4B. To mitigate discomfortto the subject and undue pressure to the detector unit, each detectorunit may be provided with various sensors. As a first example, and asshown in FIGS. 5A-5C, a pair of optical sensors may be included in thedetector unit and may project light from a light-emitting diode (LED)therebetween, such that when an object (e.g., the subject to be imaged)obscures or obstructs the LED light, the detector unit may retract. As asecond example, and as shown in FIGS. 6A-6C, a pair of pressure-basedsliding-end contact sensors may also be included in the detector unitand may trigger pivoting of the detector unit away from an object (e.g.,the subject to be imaged) when one of the sliding-end contact sensors iscontacted and actuated by the object.

The detector array, and the individual detector units therein, may becontrolled via a controller unit of the NM imaging system to conform toan outer perimeter of the subject to be imaged. Exemplary routines whichmay be implemented include the methods provided in FIGS. 8 and 9 forimaging the subject with sufficient angular resolution and positioningthe detector units therefor.

FIG. 1 is a schematic illustration of a NM imaging system 100 having aplurality of imaging detectors mounted on a gantry. The imagingdetectors may be configured to rotate around a fixed pivot. The movementof the imaging detectors may be controlled to reduce the likelihood of,or avoid, collision among the moving imaging detectors and/or reduce thelikelihood of one imaging detector obstructing the field of view ofanother imaging detector. For example, the NM imaging system in someembodiments provides coordinated swinging or pivoting motion of aplurality of imaging detectors or detector units therein.

In particular, a plurality of imaging detectors 102 are mounted to agantry 104 and/or a patient support structure (not shown) (e.g., under apatient table 120), which may define a table support for the patienttable 120. In the illustrated embodiment, the imaging detectors 102 areconfigured as a detector array 106 positioned around the subject 110(e.g., a patient), as viewed in FIG. 1. The detector array 106 may becoupled directly to the gantry 104, or may be coupled via supportmembers 112 thereto, to allow movement of the entire detector array 106relative to the gantry 104 (e.g., rotational movement in the clockwiseor counter-clockwise direction as viewed in FIG. 1). Additionally, eachof the imaging detectors 102 may include a detector unit 114, each ofwhich may be mounted to a movable detector carrier 116 (e.g., a supportarm or actuator that may be driven by a motor to cause movement thereof)that extends from the gantry 104. In some embodiments, each of thedetector units 114 may be positioned outside of (e.g., at an end of) arespective detector carrier 116 nearest a center of an aperture 118 ofthe gantry 104.

In some embodiments, the detector carriers 116 may allow movement of thedetector units 114 toward and away from the subject 110, such aslinearly. Thus, in the illustrated embodiment, the detector array 106 isaround the subject 110 and may allow linear movement of the detectorunits 114, such as toward or away from the patient table 120 in oneembodiment. However, other configurations and orientations are possibleas described herein, as well as different types of movements (e.g.,transverse or perpendicular movement relative to the patient table 120).It should be noted that the movable detector carrier 116 may be any typeof support that allows movement of the detector units 114 relative tothe support member 112 and/or gantry 104, which in various embodimentsallows the detector units 114 to move linearly toward and away from thesupport member 112, such as radially inward and outwards for positioningadjacent the subject 110. For example, as described herein, the detectorunits 114 may be controlled to move independently of each other towardor away from the subject 110, as well as capable of rotational,pivoting, or tilting movement in some embodiments.

Each of the imaging detectors 102 in various embodiments may be smallerthan a conventional whole body or general purpose imaging detector. Aconventional imaging detector may be large enough to image most or allof a width of a patient's body at one time and may have a diameter ofapproximately 50 cm or more. In contrast, each of the imaging detectors102 may include one or more detector units 114 coupled to respectivedetector carrier(s) 116 and having dimensions of 4 cm to 32 cm and maybe formed of a plurality of CZT tiles or modules. As an example, each ofthe detector units 114 may be 16×32 cm in size and may be composed of 21CZT pixelated modules (not shown at FIG. 1). For example, each modulemay be 4×4 cm in size and have 16×16 (=256) pixels. In some embodiments,each detector unit 114 may include a plurality of modules, such as anarray of 3×8 modules, 2×8 modules, 3×7 modules, or 2×7 modules, forexample. However, different configurations and array sizes may becontemplated without departing from the scope of the present disclosure.

It should be understood that the imaging detectors 102 and/or thedetector units 114 may be different sizes and/or shapes with respect toeach other, such as square, rectangular, circular, or another shape. Anactual field of view (FOV) of each of the imaging detectors 102 may bedirectly proportional to the size and shape of the respective imagingdetector 102 and detector unit 114. In some embodiments, each of theimaging detectors 102 may have a same configuration as each otherimaging detector 102. Thus, in such embodiments, each of the detectorunits 114 respectively included in the imaging detectors 102 may have asame configuration as each other detector unit 114. In one embodiment,each of the detector units 114 may have a rectangular shape, such thateach CZT module in a given row of CZT modules may be equidistant from asurface 115 of a given detector unit 114.

It will be appreciated that a number of imaging detectors 102 may varybetween embodiments and is only to be limited by practical constraintsand not by the exemplary embodiments discussed in the presentdisclosure. A lower limit of the number of imaging detectors 102 may beselected to provide a threshold amount of imaging coverage. An upperlimit of the number of imaging detectors may be selected to prevent anygiven imaging detector 102 obscuring the FOV of another imaging detector102. In exemplary embodiments, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12imaging detectors 102 may be included in the detector array 106.

The gantry 104 may be formed with the aperture 118 (e.g., cylindricalopening or bore) therethrough as illustrated. The patient table 120 maybe configured with a support mechanism, such as the patient supportstructure, to support and carry the subject 110 in one or more of aplurality of viewing positions within the aperture 118 and relative tothe imaging detectors 102. Alternatively, the gantry 104 may include aplurality of gantry segments (not shown), each of which mayindependently move a given support member 112 or one or more of theimaging detectors 102.

The gantry 104 may also be configured in other shapes, such as a “C,”“H,” or “L,” for example, and may be rotatable about the subject 110.For example, the gantry 104 may be formed as a closed ring or circle, oras an open arc or arch which allows the subject 110 to be easilyaccessed while imaging and facilitates loading and unloading of thesubject 110, as well as reducing claustrophobia in some subjects 110.For example, in some embodiments the gantry 104 may be arc-shaped andthe support members 112 movable along the arc to position the imagingdetectors 102 at different locations along the gantry 104. In someembodiments, the imaging detectors 102 may also be independently movablealong the gantry 104.

Additional imaging detectors (not shown) may be positioned to form rowsof detector arrays or an arc or ring around the subject 110. Bypositioning multiple imaging detectors 102 at multiple positions withrespect to the subject 110, such as along an imaging axis (e.g.,head-to-toe direction of the subject 110), image data specific for alarger FOV may be acquired more quickly.

Each of the detector units 114 may include a radiation detection face,which may be directed toward the subject 110 or a region of interestwithin the subject 110. The radiation detection faces may each becovered by or have coupled thereto a collimator 122. The actual FOV foreach of the imaging detectors 102 may be increased, decreased, orrelatively unchanged by the type of collimator 122. In one embodiment,the collimator 122 is a multi-bore collimator, such as a parallel-holecollimator. However, other types of collimators, such as converging ordiverging collimators may optionally or alternatively be used. Otherexamples for the collimator 122 include slanthole, pinhole,parallel-beam converging, diverging fan-beam, converging or divergingcone-beam, multi-bore converging, multi-bore converging fan-beam,multi-bore converging cone-beam, multi-bore diverging, or other types ofcollimators.

The detector units 114 may be configured such that a given collimator122 may be exchanged for another collimator, e.g., to suit a differentapplication. For example, a slanthole collimator may be used to directradiation to and from an organ partially blocked from view. As anotherexample, a pinhole collimator may be used to image a relatively smallstructure, such as a thyroid or a joint. In some embodiments, a givendetector unit 114 may be fit with one type of collimator 122 and anotherdetector unit 114 may be fit with another type of collimator 122. Itwill therefore be appreciated that many configurations of collimators122 may be contemplated and implemented within the scope of the presentdisclosure. In this way, a breadth of imaging applications may beincreased by varying types and configurations of collimators 122 in thedetector units 114.

Optionally, multi-bore collimators may be constructed to be registeredwith pixels of the detector units 114, which in one embodiment are CZTdetectors. However, other materials may be used. Registered collimationmay improve spatial resolution by forcing photons going through one boreto be collected primarily by one pixel. Additionally, registeredcollimation may improve a sensitivity and energy response of pixelateddetectors as detector area near the edges of a pixel or in between twoadjacent pixels may have reduced sensitivity or decreased energyresolution or other performance degradation. Having collimator septadirectly above the edges of pixels reduces the chance of a photonimpinging at these degraded performance locations, without decreasingthe overall probability of a photon passing through the collimator.Further, in some embodiments, the detector units 114 may not be fit toexternal covers. As such, the detector units 114 may move such that asurface thereof is as close as possible to the subject 110, therebyincreasing an imaging sensitivity of the NM imaging system 100. As aresult, however, a pivoting motion of the detector units 114 may belimited in some embodiments to avoid or limit contact with the subject110.

In some embodiments, the detector units 114 may each be provided with aplurality of proximity detectors (not shown at FIG. 1, but described indetail below with reference to FIG. 2). Each of the plurality ofproximity detectors may include respective pressure sensors, opticalsensors, capacitive sensors, and/or ultrasound sensors disposed at eachcorner adjacent to the surface 115. Feedback from a sensor included in agiven detector unit 114 may indicate that the given detector unit 114 iswithin a threshold distance of the subject 110, the patient table 120,or another detector unit 114, and the given detector unit 114 mayautomatically retract or otherwise move. In additional or alternativeembodiments, an LED beam may be projected between the pair of sensors.In such embodiments, if the LED beam is interrupted, the correspondingdetector unit 114 may automatically retract or otherwise move (asdescribed in detail below with reference to FIGS. 5A-6C). In additionalor alternative embodiments, automatic body contouring may be implementedvia optical feedback, such that an outer perimeter of the subject 110may be approximated and the detector units 114 may automatically avoidthe subject 110.

A controller unit 130 may control the movement and positioning of thepatient table 120, imaging detectors 102, gantry 104, and/or thecollimators 122. A range of motion before or during an acquisition, orbetween different image acquisitions, is set to maintain the actual FOVof each of the imaging detectors 102 directed, for example, toward or“aimed at” a particular area or region of the subject 110 or along theentire subject 110.

The controller unit 130 may have a gantry motor controller 132, tablecontroller 134, detector controller 136, pivot controller 138, andcollimator controller 140. The controllers 132, 134, 136, 138, 140 (thatis, the controller unit 130) may be automatically commanded by aprocessing unit 150, manually controlled by an operator, or acombination thereof. The gantry motor controller 132 may move theimaging detectors 102 with respect to the subject 110, for example,individually, in segments or subsets, or simultaneously in a fixedrelationship to one another. For example, in some embodiments, thegantry motor controller 132 may cause the imaging detectors 102 and/orone or more of the support members 112 to rotate about the subject 110,which may include motion of less than or up to 180 degrees (or more).

The table controller 134 may move the patient table 120 to position thesubject 110 relative to the imaging detectors 102. The patient table 120may be moved in up-down directions, in-out directions, and right-leftdirections, for example. As a specific example, a large region ofinterest of the subject 110 (e.g., metastasis) may be imaged withrelatively few imaging detectors 102 by moving the patient table 120through an area of the gantry 104 having the imaging detectors 102 suchthat the same imaging detectors 102 may perform a scan of the entireregion of interest.

The detector controller 136 may control movement of each of the imagingdetectors 102 to move closer to and farther from a surface of thesubject 110, such as by controlling translating movement of the detectorcarriers 116 linearly toward or away from the subject 110 (e.g., slidingor telescoping movement). Optionally, the detector controller 136 maycontrol movement of the detector carriers 116 to allow coordinatedmovement of the detector array 106. The pivot controller 138 may controlpivoting, rotating, or swinging movement of the detector units 114 atends of the detector carriers 116, and/or the detector carrier 116. Forexample, one or more of the detector units 114 or detector carriers 116may be pivoted or swung about at least one axis to view the subject 110from a plurality of angular orientations. The collimator controller 140may adjust a position of an adjustable collimator, such as a collimatorwith adjustable strips (or vanes) or adjustable pinhole(s).

It should be noted that motion of one or more imaging detectors 102 maybe in directions other than strictly axially or radially, andoptionally, motions in several motion directions may be used. Moreover,the motions of the imaging detectors 102 are coordinated in variousembodiments as described herein. Therefore, the term “motion controller”may be used to indicate a collective name for all motion controllers(e.g., controllers 132, 136, 138). It should be noted that the variouscontrollers may be combined, for example, the detector controller 136and pivot controller 138 may be combined to provide the differentmovements described herein.

Prior to acquiring an image of the subject 110 or a portion of thesubject 110, the imaging detectors 102, gantry 104, patient table 120,and/or collimators 122 may be adjusted as discussed in more detailherein, such as to first or initial imaging positions, as well assubsequent imaging positions. The imaging detectors 102 may each bepositioned to image a portion of the subject 110. Alternatively, one ormore of the imaging detectors 102 may not be used to acquire data.Positioning may be accomplished manually by the operator and/orautomatically, which may include using other images acquired before thecurrent acquisition, such as by another imaging modality such ascomputed tomography (CT), magnetic resonance imaging (MRI), x-ray,positron emission tomography (PET), or ultrasound. Additionally, thedetector units 114 may be configured to acquire non-NM data, such asx-ray CT data.

After the imaging detectors 102, gantry 104, patient table 120, and/orcollimators 122 are positioned, one or more images may be acquired byone or more of the imaging detectors 102 being used, which may includepivoting or swinging motion of one or more of the detector units 114,which may pivot, rotate, or swing to different degrees or betweendifferent ranges of angles. The image data acquired by each imagingdetector 102 may be combined and reconstructed into a composite image,which may include two-dimensional (2D) images, a three-dimensional (3D)volume, or a 3D volume over time, e.g., four dimensions (4D).

In one embodiment, the imaging detectors 102, gantry 104, patient table120, and/or collimators 122 may remain stationary after being initiallypositioned. In another embodiment, an effective FOV for one or more ofthe imaging detectors 102 may be increased by movement such as pivoting,rotating, or swinging one or more of the imaging detectors 102, rotatingthe detector array 106 with the gantry 104, adjusting one or more of thecollimators 122, or moving the patient table 120.

In various embodiments, a data acquisition system (DAS) 160 may receiveelectrical signal data produced by the imaging detectors 102 andconverts the electrical signal data into digital signals for subsequentprocessing. An image reconstruction device 162 and a data storage device164 may be provided in addition to the processing unit 150. It should benoted that one or more functions related to one or more of dataacquisition, motion control, data processing, and image reconstructionmay be accomplished through hardware, software, and/or by sharedprocessing resources, which may be located within or near the NM imagingsystem 100, or may be located remotely. Additionally, a user inputdevice 166 may be provided to receive user inputs (e.g., controlcommands), as well as a display 168 for displaying images.

Additionally, a detector position controller 165 may also be provided,which may be implemented in hardware, software, or a combinationthereof. For example, as shown in FIG. 1, the detector positioncontroller 165 may form part of, or operate in connection with, theprocessing unit 150. In some embodiments, the detector positioncontroller 165 may be a module that operates to control the movement ofthe imaging detectors 102, including the detector units 114, such thatcoordinated or synchronized movement is provided as described herein. Itshould be noted that movement of a plurality of the imaging detectors102 and/or detector units 114 may be performed at the same time (e.g.,simultaneously or concurrently) or at different times (e.g.,sequentially or step-wise, such as back and forth between two detectorunits 114). It also should be understood that when referring to adetector unit, such a detector unit may include one or multiple detectormodules (e.g., CZT modules).

Referring now to FIG. 2, a cross-sectional view of the detector unit 114is depicted, showing three CZT modules 204, each indicative of a row ofmultiple CZT modules 204. It will be appreciated that in FIG. 2, and inFIG. 3 (described in more detail below), mutually perpendicular axes251, 252, and 253 define a three-dimensional space relative to thecross-sectional view, where the axis 251 and the axis 253 define a planeof the cross-sectional view and the axis 252 is normal to the plane ofthe cross-sectional view. Herein, the mutually perpendicular axes 251,252, and 253 may be employed to describe an overall movement of thedetector unit 114, as well as relative positioning of components of thedetector unit 114 with respect to one another. For example, each of thethree rows of CZT modules 204 may be respectively aligned with thedepicted CZT modules 204 and may extend along the axis 252, such thatone or more CZT modules 204 may be in front of the plane of thecross-sectional view and one and/or one or more CZT modules 204 may bebehind the plane of the cross-sectional view.

The detector unit 114 may include a casing 202 which may house one ormore of the various components of the detector unit 114, where thecasing 202 may be a frame or other support structure. The casing 202 maybe made of a high-density material, such as lead or tungsten, forexample. The collimator 122 may be disposed within the casing 202. Inspecific embodiments wherein the collimator 122 is exchangeable, thecollimator 122 may be removably fixed in place by a pair of adjustablelocking mechanisms 222 such that the collimator 122 may be attached anddetached upon application of pressure to each of the pair of adjustablelocking mechanisms 222. The collimator 122 may include a plurality ofsepta, which may be configured to receive and narrow incoming radiation(e.g., gamma rays) for the CZT modules 204. The incoming radiation maybe passed to CZT detector plates 206 respectively situated in the CZTmodules 204. Each of the CZT modules 204 may further include electronics208 (e.g., output electronics to output detected events) conductivelycoupling the CZT detector plate 206 to a printed circuit board (PCB)210, such that NM imaging data may be acquired based on the incomingradiation. The NM imaging data may then be passed to the controller unit(e.g., 130) and the processing unit (e.g., 150) of the NM imaging system(e.g., 100), as described above with reference to FIG. 1. A heat sink(e.g., air or water cooling) 212 with a fan (not shown) may be disposedon, or positioned within, the casing 202, so as to prevent overheatingof the various components therein during operation of the detector unit114.

The detector unit 114 may include a pair of proximity detectors 215actuatable by optical feedback such that contact with the subject (e.g.,110) by the detector unit 114 may be mitigated or avoided. As shown, thepair of proximity detectors 215 may be disposed opposite to one another,such that each of the pair of proximity detectors 215 reflects anopposite proximity detector 215 across a plane parallel to a planeincluding the axes 252 and 253. It will be appreciated that the pair ofproximity detectors 215 may include any type of proximity sensor knownin the art, such as further pressure sensors, optical sensors,capacitive sensors, and/or ultrasound sensors, within the scope of thepresent disclosure. For example, and as depicted at FIG. 2, the pair ofproximity detectors 215 may respectively include a pair of opticalsensors 216 a, 216 b. The optical sensor 216 a may be operable toproject an LED beam 218 along the axis 251 and across a cavity 220formed by the proximity detectors 215 extending from the surface 115along the axis 253. Assuming no obstructing or obscuring object entersthe cavity 220, the LED beam 218 may correspondingly be received by theoptical sensor 216 b. However, in some examples, an interfering object(e.g., a portion of the subject) may indeed enter the cavity 220. Insuch examples, the LED beam 218 may be interrupted and thereby preventedfrom reaching the optical sensor 216 b. As such, appropriate movement ofthe detector unit 114 may be automatically actuated so that theinterfering object and/or the detector unit 114 is not subjected toundue pressure (e.g., the detector unit 114 may translate along the axis253 away from the interfering object, as described in detail withreference to FIGS. 5A-5C below).

Each of the pair of proximity detectors 215 may additionally oralternatively include a sliding-end contact sensor 214. The sliding-endcontact sensors 214 may be actuated (e.g., depressed along the axis 253)by a threshold pressure applied thereto by an interfering object (e.g.,a portion of the subject, e.g., 110, or another detector unit 114).Thus, and as described in detail below with reference to FIGS. 6A-6C,when the interfering object actuates at least one of the sliding-endcontact sensors 214, the LED beam 218 may be interrupted and thereforemay not reach the optical sensor 216 b. As such, appropriate movement ofthe detector unit 114 may be automatically actuated so that theinterfering object and/or the detector unit 114 is not subjected toundue pressure (e.g., the detector unit 114 may pivot away from theinterfering object around an axis parallel to the axis 252).

The detector unit 114 provided by an embodiment of the presentdisclosure may be optimized for flexible, high-resolution NM imaging. Asa first example, no obstructing external housing may be disposed aroundthe detector unit 114, permitting the detector unit 114 to be moved asclose as possible to the subject (e.g., 110) to be imaged. Indeed, theproximity detectors 215 may preclude use of such external housings, asthe proximity detectors 215 may mitigate discomfort to the subject byautomatically adjusting the detector unit 114 near to, but not incontact with, the subject upon actuation of at least one of theproximity detectors 215. As a second example, the multiple rows of CZTmodules 204 may provide proportionally greater imaging resolution to thedetector unit 114 as compared to a detector unit having a single row ofCZT modules, as the multiple rows of CZT modules 204 may provideincreased image sampling. Thus, in the depicted example, the detectorunit 114, having three rows of CZT modules 204, may correspondingly havethree times the imaging resolution of a detector unit having a singlerow of CZT modules. As a third example, and as described in detail belowwith reference to FIG. 3, the detector unit 114 may be configured tomove along multiple degrees of freedom, facilitating conformation of thedetector unit 114, and thus the entire detector array (e.g., 106), tothe subject. In this way, an amount of “dead shielding” space (e.g.,imaged space not corresponding to the subject) may be reduced.

Referring now to FIG. 3, a schematic diagram 300 of the imaging detector102 including the detector unit 114 and the detector carrier 116 isdepicted. Further shown are a number of degrees of freedom of thedetector unit 114 which may be actuated by various mechanical componentsof the NM imaging system (e.g., 100) and controlled by the controllerunit (e.g., 130) thereof. For example, the imaging detector 102 may beaffixed to the gantry 104, or support members thereof (e.g., 112), suchas a track 304. In some embodiments, the track 304 may circumscribe aninner surface 306 of the gantry 104, where the imaging detector 102 maybe positioned partially within the track 304. Specifically, in someexamples, the track 304 may be an open space through which the detectorcarrier 116 may extend from an internal rotational mechanism. In otherexamples, a support mechanism to facilitate movement, such as wheels,may be placed within the track and coupled to the detector carrier 116.As such, the imaging detector 102 may move with the gantry 104 or maymove independently from the gantry 104 along the track 304. Further, theimaging detector 102 may extend within the aperture (e.g., 118; notshown at FIG. 3) of the gantry 104. Specifically, the imaging detector102 may extend orthogonally toward a rotational axis 308 located at acenter of the gantry 104 and tracing a length of the aperture thereof.Carried by the detector carrier 116, the detector unit 114 may thereforerotate 302 around the rotational axis 308 (not shown to scale). Asshown, the rotational axis 308 may be parallel to the axis 252. It willbe appreciated that, in embodiments wherein the gantry 104 is configuredin an annular shape (as depicted in FIG. 1), the detector unit 114 mayfully, or completely, rotate 302 around the rotational axis 308.However, in other examples, any given detector unit 114 in the detectorarray (e.g., 106) may have limited rotation 302 about the rotationalaxis 308, such as up to 180°, 90°, 60°, etc.

As another example, the detector carrier 116 may include a plurality oftelescoping segments (e.g., 314 a, 314 b, 314 c). The plurality oftelescoping segments may collapse into one another toward the gantry 104along the axis 253. For example, the telescoping segment 314 a maycollapse into the telescoping segment 314 b and the telescoping segment314 b may collapse into the telescoping segment 314 c, such that theplurality of telescoping segments may be in a fully collapsed, orretracted, position. The schematic diagram 300, however, depicts theplurality of telescoping segments in a fully extended position. In thisway, the detector unit 114 may translate 312 along the axis 253 withinphysical limitations of the detector carrier 116 (e.g., the detectorcarrier 116 may be in any position between the fully collapsed positionand the fully extended position).

As yet another example, the detector unit 114 may be configured to pivot322 independently from the detector carrier 116. That is, while thedetector unit 114 may remain affixed to the detector carrier 116, thedetector unit 114 may pivot 322 around a pivoting axis 324 located at acenter thereof. As shown, the pivoting axis 324 may be parallel to eachof the axis 252 and the rotational axis 308. It will be appreciated thatthe detector unit 114 may not pivot completely around the pivoting axis324, as mechanical restrictions may preclude complete pivoting. However,the detector unit 114 may move within a limited range from a defaultconfiguration, such as the configuration depicted in schematic diagram300. In some embodiments, the detector unit 114 may pivot 322 up to 60°from the default configuration. In additional or alternativeembodiments, the detector unit 114 may pivot 322 up to 30° from thedefault configuration. In additional or alternative embodiments, thedetector unit 114 may pivot 322 up to 20° from the defaultconfiguration. In additional or alternative embodiments, the detectorunit 114 may pivot 322 up to 15° from the default configuration. Inadditional or alternative embodiments, the detector unit 114 may pivot322 up to 10° from the default configuration.

In this way, the detector unit 114 may at least move about onerotational axis, one translational axis, and one pivoting axis, suchthat the detector array (e.g., 106) including a plurality of detectorunits 114 may be operable to conform to a subject to be imaged. It willbe appreciated that other movements of the detector unit 114 may becontemplated and implemented by one of ordinary skill in the art, andthat the present disclosure is not to be interpreted as limited to thedegrees of freedom described with reference to FIG. 3.

Referring now to FIGS. 4A and 4B, schematic diagrams 400 and 450 aredepicted, illustrating an exemplary process for conforming the detectorarray 106 to a subject 410 (represented in FIGS. 4A and 4B as across-sectional slice thereof). As described above with reference toFIG. 1, the detector array 106 may include a plurality of imagingdetectors 102, each imaging detector 102 including the detector unit 114and the detector carrier 116. Further, the detector array 106 may beformed within the aperture 118 of the gantry 104, whereby the detectorarray 106 may be directly coupled to the gantry 104 or to the supportmembers 112 thereof.

As shown in the schematic diagram 400, the plurality of detector units114 may be configured in a number of initial positions, which may not beoptimal for imaging of the subject 410. That is, at least some of thecollimators 122 of the plurality of detector units 114 may be orientedin a direction at least partially facing away from the subject 410.Further, the plurality of detector units 114 may be retracted away fromthe subject 410 to allow the subject 410 to freely enter the aperture118, which may further preclude optimal imaging resolution.

Each of the plurality of detector units 114 may move independently toconform to the subject 410. For example, automatic body contouring maybe implemented by the NM imaging system (e.g., 100), which may providean estimated outer perimeter of the subject 410. Based on respectivepositions thereof, each of the plurality of detector units 114 maytherefore move to align toward the estimated outer perimeter. In theschematic diagram 400, for example, one of the plurality of detectorunits 114 is shown as translating 402 toward the subject 410. The one ofthe plurality of detector units 114 is further shown as pivoting 404 soas to align the collimator 122 thereof for optimal receipt of incomingradiation from the subject 410. Each remaining detector unit 114 maysimilarly adjust a position thereof to acquire NM imaging data of anincreased imaging resolution.

As such, the plurality of detector units 114 may move to a finalposition, as depicted in the schematic diagram 450. In this way, thedetector array 106 may be optimized for subjects of varying sizes andshapes, providing an NM imaging system with high imaging flexibility. Asshown, the final position of the plurality of detector units 114 may beadjacent to, but not in contact with, the subject 410.

In some embodiments, automatic body contouring alone may not besufficient to prevent the plurality of detector units 114 fromcontacting the subject 410. For example, automatic body contouring mayestimate an outer perimeter of the subject 410 which, at least in part,may lie within an actual perimeter of the subject 410. Thus, when agiven detector unit 114 attempts to conform to the outer perimeterestimated by the automatic body contouring, the given detector unit 114may contact the subject 410. Such contact may be mitigated via proximitydetectors (e.g., 215) included in each detector unit 114, where theproximity detectors may include optical sensors (e.g., 216 a, 216 b) andsliding-end contact sensors (e.g., 214) for providing feedback regardingpositioning of the plurality of detector units 114 relative to an actuallocation of the subject 410 (that is, not based on the estimated outerperimeter alone).

Referring now to FIGS. 5A-5C, schematic diagrams 500, 520, 540 aredepicted, illustrating an exemplary process for adjusting a position ofthe imaging detector 102 when the detector unit 114 thereof moves near asubject 502 via extension of the detector carrier 116. The detector unit114 may include the pair of proximity detectors 215, where the pair ofproximity detectors 215 may respectively include one of the opticalsensors 216 a, 216 b. As such, feedback from the proximity detectors 215may be utilized by the controller unit (e.g., 130) described above withreference to FIG. 1 to determine a proximity of the detector unit 114 tothe subject 502. It will be appreciated that the subject 502 is depictedin the schematic diagrams 500, 520, 540 as a portion thereof, and thatthe subject 502 may extend beyond the dashed line 504.

As shown in the schematic diagram 500, the detector carrier 116 mayextend in a direction 506, translating the detector unit 114 toward thesubject 502. As described in detail above with reference to FIG. 3, thedetector carrier 116 may include the plurality of telescoping segments(not shown at FIGS. 5A-5C), enabling such extension of the detectorcarrier 116. As further shown, the optical sensor 216 a may project theLED beam 218, which may be correspondingly received by the opticalsensor 216 b.

After extension of the detector carrier 116, the detector unit 114 maybe positioned as shown in the schematic diagram 520. As shown, a portionof the subject 502 may obstruct 522 the LED beam 218 from reaching theoptical sensor 216 b. As such, feedback from the optical sensor 216 b,or lack thereof, may indicate that the detector unit 114 has beenpositioned too close to, but may not be contacting, the subject 502.

As such, and as shown in the schematic diagram 540, the detector carrier116 may retract in the direction 542, translating the detector unit 114away from the subject 502. In some examples, the detector carrier 116may be configured to retract to just beyond a predetermined distancefrom where the obstruction 522 occurred. In other examples, the detectorcarrier 116 may be configured to retract until the LED beam 218 is againreceived by the optical sensor 216 b. As such, a high imaging resolutionmay be retained by maintaining the proximity of the detector unit 114 tothe subject 502. In this way, in some examples, the detector unit 114may automatically avoid contacting the subject 502, thereby mitigatingexcess pressure on the various components of the detector unit 114 anddiscomfort to the subject 502.

Referring now to FIGS. 6A-6C, schematic diagrams 600, 620, 640 aredepicted, illustrating an exemplary process for adjusting a position ofthe imaging detector 102 when the detector unit 114 thereof moves near asubject 602 via extension of the detector carrier 116 or pivoting of thedetector unit 114 thereon. The detector unit 114 may include the pair ofproximity detectors 215, where the pair of proximity detectors 215 mayrespectively include one sliding-end contact sensor 214 and one of theoptical sensors 216 a, 216 b. As such, feedback from the proximitydetectors 215 may be utilized by the controller unit (e.g., 130)described above with reference to FIG. 1 to determine a proximity of thedetector unit 114 to the subject 602. It will be appreciated that thesubject 602 is depicted in the schematic diagrams 600, 620, 640 as aportion thereof, and that the subject 602 may extend beyond the dashedline 604.

As shown in the schematic diagram 600, the detector carrier 116 mayextend in a direction 606, translating the detector unit 114 toward thesubject 602. As described in detail above with reference to FIG. 3, thedetector carrier 116 may include the plurality of telescoping segments(not shown at FIGS. 6A-6C), enabling such extension of the detectorcarrier 116. In some examples, the detector unit 114 may additionallypivot toward the subject 602. As further shown, the optical sensor 216 amay projected the LED beam 218, which may be correspondingly received bythe optical sensor 216 b.

After extension of the detector carrier 116 and/or pivoting of thedetector unit 114, the detector unit 114 may be positioned as shown inthe schematic diagram 620. As shown, the detector unit 114 may contact622 the subject 602, thereby actuating (e.g., depressing) one of thesliding-end contact sensors 214. Once actuated, the sliding-end contactsensor 214, being mechanically coupled to the optical sensor 216 b, maymove the optical sensor 216 b out of a path of the LED beam 218. Assuch, feedback from the optical sensor 216 b, or lack thereof, mayindicate that the detector unit 114 has pivoted such that a cornerthereof including one of the pair of proximity detectors 215 hascontacted the subject 602.

As such, and as shown in the schematic diagram 640, the detector unit114 may pivot in the direction 642, moving the detector unit 114 awayfrom the subject 602. The detector unit 114 may be configured to pivotuntil the actuated sliding-end contact sensor 214 returns to a defaultposition (e.g., the position depicted by the schematic diagrams 600,640), such that a high imaging resolution may be retained by maintainingthe proximity of the detector unit 114 to the subject 602. In this way,in some examples, the detector unit 114 may automatically pivot awayfrom the subject 602 upon actuation of the sliding-end contact sensor214 under light pressure, thereby mitigating excess pressure on thevarious components of the detector unit 114 and discomfort to thesubject 602. It will further be appreciated that, though the pair ofsliding-end contact sensors 214 are coupled with the pair of opticalsensors 216 a, 216 b in the exemplary process depicted by FIGS. 6A-6C,that the exemplary process may be executed based on the pressurefeedback received by at least one of the pair of sliding-end contactsensors 214 absent the pair of optical sensors 216 a, 216 b.

Referring now to FIGS. 7A-7E, schematic diagrams 700, 720, 740, 760, 780are depicted, showing various exemplary configurations of the gantry 104and the detector array 106. The detector array 106 may either be affixedto the gantry 104 or to the support members 112 thereof. As shown, thedetector array 106 may include the plurality of imaging detectors 102,each of the plurality of imaging detectors 102 respectively includingthe detector unit 114 positioned on the detector carrier 116. Each ofthe detector units 114 may respectively include the collimator 122 forreceiving and focusing incoming radiation from a subject (not shown atFIGS. 7A-7E). In the exemplary configurations of FIGS. 7A-7E, the gantry104 is configured as a substantially circular ring having thecylindrical aperture 118 therethrough. It will be appreciated, however,that the exemplary configurations of FIGS. 7A-7E are not to beinterpreted as limiting the present disclosure, and that anyconfiguration of the detector array 106 and the gantry 104 may becontemplated and implemented by one of ordinary skill in the art.

As a first example, and as shown in the schematic diagram 700, thedetector array 106 may include two imaging detectors 102 positioned in adefault configuration (e.g., prior to movements of individual imagingdetectors 102) on the gantry 104 spaced approximately 180° from oneanother (e.g., opposite to one another). As a second example, and asshown in the schematic diagram 720, the detector array 106 may includethree imaging detectors 102 positioned in a default configuration (e.g.,prior to movements of individual imaging detectors 102) on the gantry104 spaced approximately 120° from one another. As a third example, andas shown in the schematic diagram 740, the detector array 106 mayinclude six imaging detectors 102 positioned in a default configuration(e.g., prior to movements of individual imaging detectors 102) on thegantry 104 spaced approximately 60° from one another. As a fourthexample, and as shown in the schematic diagram 760, the detector array106 may include nine imaging detectors 102 positioned in a defaultconfiguration (e.g., prior to movements of individual imaging detectors102) on the gantry 104 spaced approximately 40° from one another. As afifth example, and as shown in the schematic diagram 780, the detectorarray 106 may include twelve imaging detectors 102 positioned in adefault configuration (e.g., prior to movements of individual imagingdetectors 102) on the gantry 104 spaced approximately 30° from oneanother.

Referring now to FIG. 8, a flow chart is depicted, showing a method 800for imaging a subject via an NM imaging system. Execution of the method800 may depend upon various degrees of freedom via which detector unitsof the NM imaging system may move, such that the detector units arepositioned to optimally image a subject.

Method 800 is described below with regard to the systems and componentsdepicted in FIGS. 1 and 2, though it should be appreciated that method800 may be implemented with other systems and components withoutdeparting from the scope of the present disclosure. In some embodiments,method 800 may be implemented as executable instructions in anyappropriate combination of the NM imaging system 100, an edge device(e.g., an external computing device) connected to the NM imaging system100, a cloud in communication with the NM imaging system 100, and so on.As one example, method 800 may be implemented in non-transitory memoryof a computing device, such as the processing unit 150 of the NM imagingsystem 100 in FIG. 1 (e.g., in communication with the controller unit130 of the NM imaging system 100).

Method 800 may begin at 805, where an NM imaging scan may be initiated.The NM imaging scan may include receiving incoming radiation from thesubject (e.g., 110) at the detector units (e.g., 114). However, each ofthe detector units may not yet be positioned for optimal imaging by theNM imaging system (e.g., 100), and therefore, at 810, method 800 mayinclude positioning the detector units prior to actively acquiring NMimaging data at 815. Positioning the detector units may includetranslating and/or pivoting the detector units via various degrees offreedom such that the detector units may be positioned adjacent to, butnot in contact with, the subject. In this way, the detector units may becoordinated to move to a first position to receive the incomingradiation from the subject.

Once the detector units (e.g., 114) are positioned, the incomingradiation may pass through, and be narrowed by, the collimators (e.g.,122) associated with the various detector units. The incoming radiationmay be passed to respective CZT modules (e.g., 204), such that, at 815,the NM imaging data may be acquired.

At 820, method 800 may include determining whether sufficient angularresolution of the NM imaging data has been obtained by the detectorarray (e.g., 106). In some embodiments, the detector array may berotated via the gantry (e.g., 104) such that individual imagingdetectors (e.g., 102) do not superimpose a prior angular position of anyother imaging detector. For example, if the imaging detectors aredisposed every 60° around a circular gantry, then the gantry may rotateby less than 60° (referred to herein as a resolution angle) and thesubject (e.g., 110) may be reimaged to obtain further angularresolution.

Specifically, if sufficient angular resolution has not been obtained bythe detector array (e.g., 106), method 800 may proceed to 825 to retractthe detector units (e.g., 114) via the detector carriers (e.g., 116). Insome embodiments, retracting the detector units via the detectorcarriers may include collapsing a plurality of telescoping segments ofthe detector carriers to a fully collapsed position. Once the detectorunits are retracted, method 800 may include, at 830, rotating the gantry(e.g., 104) by the resolution angle. Method 800 may then return to 810to again position the detector units for imaging. In this way, thedetector units may be coordinated to move to a second position toreceive further incoming radiation from the subject.

If sufficient angular resolution has been obtained by the detector array(e.g., 106), method 800 may proceed to 835 to finish the NM imaging scan(e.g., no further NM imaging data may be acquired until another NMimaging scan is initiated). Then, at 840, method 800 may includediagnosing a medical issue based on the NM imaging data. Diagnosing themedical issue may be performed by a medical professional upon analysisof the NM imaging data acquired during the NM imaging scan. For example,an area within the subject (e.g., 110) may be afflicted by a medicalissue. The area within the subject may be imaged during the NM imagingscan, and the NM imaging system (e.g., 100) provided by an embodiment ofthe present disclosure may generate more precise and consistent NMimaging data as compared to conventional NM imaging systems. In thisway, an accuracy of the diagnosis of the medical issue may be improvedand may be made more consistent between medical professionals. Method800 may then end.

Referring now to FIG. 9, a flow chart is depicted, showing a method 900for positioning a detector array of an NM imaging system to image asubject. Execution of the method 900 may depend upon various degrees offreedom via which detector units of the detector array may move, suchthat the detector units are positioned to optimally image a subject. Assuch, in some examples, method 900 may be used in place of 810 and 815of method 800, whereby method 800 may continue at 820 followingcompletion of method 900.

Method 900 is described below with regard to the systems and componentsdepicted in FIGS. 1 and 2, though it should be appreciated that method900 may be implemented with other systems and components withoutdeparting from the scope of the present disclosure. In some embodiments,method 900 may be implemented as executable instructions in anyappropriate combination of the NM imaging system 100, an edge device(e.g., an external computing device) connected to the NM imaging system100, a cloud in communication with the NM imaging system 100, and so on.As one example, method 900 may be implemented in non-transitory memoryof a computing device, such as the processing unit 150 of the NM imagingsystem 100 in FIG. 1 (e.g., in communication with the controller unit130 of the NM imaging system 100).

Method 900 may begin at 905, where an NM imaging scan may be initiated.The NM imaging scan may include receiving incoming radiation from thesubject (e.g., 110) at the detector units (e.g., 114). However, each ofthe detector units may not yet be positioned for optimal imaging by theNM imaging system (e.g., 100). As such, method 900, from 910 to 950, mayinclude determining a final position for the detector units prior toactively acquiring NM imaging data at 955.

Such a determination of the final position for the detector units (e.g.,114) may begin at 910, where method 900 may include performing anautomatic body contouring routine to estimate an outer perimeter of thesubject (e.g., 110). For example, sensors included in at least onedetector unit may be operable to receive optical feedback based onexternal surfaces of the subject. As such, an approximate location ofthe subject and a volume thereof may be determined, such that the outerperimeter relative to a location of a given detector unit including thesensors may be estimated.

At 915, method 900 may include selecting one of the detector units(e.g., 114) of the detector array (e.g., 106). It will be appreciatedthat, though 915 to 950 are directed to sequential adjustment ofpositions of the various detector units in the detector array, 915 to950 may be executed simultaneously for each given detector unit in thedetector array (e.g., each of the detector units in the detector arraymay be positioned simultaneously to one another).

At 920, method 900 may include translating and pivoting the selecteddetector unit (e.g., 114) toward the estimated outer perimeter.Translation and pivoting of the selected detector unit may includemoving along various degrees of freedom (e.g., the various axes asdescribed above with reference to FIG. 3) to closely approximate theestimated outer perimeter. However, in some examples, since portions ofthe estimated outer perimeter may lie within an actual perimeter of thesubject (e.g., 110), the selected detector unit may attempt to move to aposition which may result in the detector unit contacting the subject,possibly causing the subject discomfort and subjecting the variouscomponents of the selected detector unit to undue pressure. As such,proximity of the selected detector unit to an object (e.g., the subjector another detector unit) may be detected by interruption of the LEDbeam (e.g., 218) projected between the pair of optical detectors (e.g.,216 a, 216 b) included in the selected detector unit and remediedaccordingly.

For example, at 925, method 900 may include determining whether the LEDbeam (e.g., 218) is obstructed by a first object. Specifically, theselected detector unit (e.g., 114) may include two proximity detectors(e.g., 215), each proximity detector respectively including onesliding-end contact sensor (e.g., 214) and one optical sensor (e.g., 216a, 216 b). The optical sensors may be disposed opposite one another,such that one of the optical sensors may generate the LED beam for theother optical sensor to receive. Obstruction of the LED beam maytherefore indicate that the selected detector unit is too close to thefirst object, such as the subject (e.g., 110) or another detector unit.

Thus, if the LED beam (e.g., 218) is obstructed by the first object,method 900 may proceed to 930 to reverse translation of the selecteddetector unit (e.g., 114) until the LED beam is unobstructed.Specifically, in examples wherein the first object is the subject (e.g.,110), the detector carrier (e.g., 116) mechanically coupled to theselected detector unit may retract the selected detector unit by apredetermined distance selected to retain high imaging resolution whileminimizing discomfort to the subject and pressure applied to theselected detector unit.

If the LED beam (e.g., 218) is not obstructed by the first object, or ifthe selected detector unit (e.g., 114) has been retracted by thecorresponding detector carrier (e.g., 116), method 900 may proceed to935 to determine whether the LED beam is broken as a result of contactof one of the sliding-end contact sensors (e.g., 214) with a secondobject. The sliding-end contact sensors may be disposed at cornersadjacent to the surface (e.g., 115) of the selected detector unit facingthe subject, whereby a given sliding-end contact sensor may be actuated(e.g., depressed) when the selected detector unit is pivoted toward, andthen contacts, the second object. Actuation of the sliding-end contactsensor may therefore indicate that the selected detector unit is tooclose to the second object, such as the subject (e.g., 110) or anotherdetector unit. In some embodiments, the second object may be differentfrom the first object. In other embodiments, the second object may bethe first object.

If the LED beam (e.g., 218) is broken as a result of contact of one ofthe sliding-end contact sensors (e.g., 214) with the second object,method 900 may proceed to 940 to reverse pivoting of the selecteddetector unit (e.g., 114) until the sliding-end contact sensor returnsto a default (e.g., unactuated and non-depressed) position.Specifically, since each sliding-end contact sensor may be mechanicallycoupled to one of the optical sensors (e.g., 216 a, 216 b), uponactuation the LED beam between the optical sensors may be broken.Reversing pivoting of the selected detector unit about a central axisthereof (e.g., the pivoting axis 324 as described above with referenceto FIG. 3) may free the sliding-end contact sensor from contact with thesecond object. Accordingly, the sliding-end contact sensor may return tothe default position and a path of the LED beam may be restored (thatis, one of the optical sensors may again receive the LED beam projectedby the other optical sensor). Further, in examples wherein the secondobject is the subject (e.g., 110), reversing pivoting only until thesliding-end contact sensor returns to the default position may maintaina proximity of the selected detector unit to the subject, therebyretaining high imaging resolution while minimizing discomfort to thesubject and pressure applied to the selected detector unit.

If the LED beam (e.g., 218) is not broken as a result of contact of oneof the sliding-end contact sensors (e.g., 214) with the second object,method 900 may proceed to 945 to conform the surface (e.g., 115) of theselected detector unit (e.g., 114) facing the subject (e.g., 110) to theestimated outer perimeter. Said another way, the NM imaging system(e.g., 100) may be operable to conform the selected detector unit to theestimated outer perimeter upon determination of no obstructing objectspreventing such conformation.

Once the surface (e.g., 115) of the selected detector unit (e.g., 114)facing the subject (e.g., 110) has been conformed to the estimated outerperimeter, or if pivoting of the selected detector unit has beenreversed to return either of the sliding-end contact sensors (e.g., 214)to the default position thereof, method 900 may proceed to 950 todetermine whether the selected detector unit is a last detector unit inthe detector array (e.g., 106) to be positioned. If the selecteddetector unit is not the last detector unit, method 900 may return to915 to select another detector unit for positioning.

If the selected detector unit (e.g., 114) is the last detector unit, thedetector array (e.g., 106) may be considered in position for optimalimaging. Thus, during the NM imaging scan, the incoming radiation maypass through, and be narrowed by, the collimators (e.g., 122) associatedwith the various detector units. The incoming radiation may be passed torespective CZT modules (e.g., 204) such that, at 955, the NM imagingdata may be acquired. Method 900 may then end.

In this way, an adjustable detector array is provided for a nuclearmedicine (NM) imaging system. In some embodiments, the adjustabledetector array may include a plurality of detector units, which maypivot and translate via respective detector carriers to conform to apatient to decrease an amount of “dead shielding” space, therebyincreasing an imaging sensitivity of the NM imaging system. Each of theplurality of detector units may include sliding-end contact sensorspaired with additional optical sensors. A technical effect of includingthe sliding-end contact sensors and the additional optical sensors isthat the NM imaging system may detect when a given detector unit iswithin a threshold distance of the patient to be imaged, and may makecorresponding adjustments to mitigate patient discomfort. Further, eachof the plurality of detector units may include multiple rows of cadmiumzinc telluride (CZT) modules with an exchangeable collimator foracquiring imaging data (e.g., receiving photons). A technical effect ofincluding multiple rows of CZT modules (as opposed to a single row) isthat the imaging sensitivity of the NM imaging system may further beincreased. Further, the exchangeable collimator may provide imagingflexibility, as different collimators may be fit to the plurality ofdetector units depending on imaging application. As a result of theincreased imaging sensitivity and flexibility, fewer detector units maybe employed to achieve a given imaging resolution, thereby reducing anoverall cost of the NM imaging system.

In one embodiment, a detector array comprises a plurality of adjustableimaging detectors, each of the plurality of adjustable imaging detectorscomprising a detector unit, each detector unit having a plurality ofrows of detector modules, wherein the plurality of adjustable imagingdetectors are arranged on an annular gantry, the annular gantryconfigured for rotation about a first axis of a cylindrical aperture ofthe annular gantry, the first axis extending a length of the cylindricalaperture, and wherein each of the plurality of adjustable imagingdetectors is disposed within the cylindrical aperture and extendsorthogonally toward the first axis. In a first example of the detectorarray, the plurality of adjustable imaging detectors are affixed to aninner surface of the annular gantry. In a second example of the detectorarray, optionally including the first example of the detector array, theannular gantry comprises a track circumscribed by an inner surface ofthe annular gantry, and the plurality of adjustable imaging detectorsare positioned partially within the track such that each of theplurality of adjustable imaging detectors is operable to moveindependently along the track with respect to each other adjustableimaging detector. In a third example of the detector array, optionallyincluding one or more of the first and second examples of the detectorarray, each of the plurality of adjustable imaging detectors comprises atelescoping detector carrier, where each detector unit is respectivelypositioned at an end of each telescoping detector carrier nearest thefirst axis and each telescoping detector carrier is configured to extendtoward or retract from the first axis. In a fourth example of thedetector array, optionally including one or more of the first throughthird examples of the detector array, the first axis is located at acenter of the cylindrical aperture, and the annular gantry is configuredfor full rotation about the first axis. In a fifth example of thedetector array, optionally including one or more of the first throughfourth examples of the detector array, each detector unit is configuredto pivot about a second axis up to 60° from a default configuration,where each second axis is respectively located at a center of eachdetector unit and each second axis is parallel with the first axis. In asixth example of the detector array, optionally including one or more ofthe first through fifth examples of the detector array, each detectormodule is a cadmium zinc telluride module. In a seventh example of thedetector array, optionally including one or more of the first throughsixth examples of the detector array, each detector unit comprises threerows of detector modules, and each of the three rows of detector modulescomprises seven detector modules. In an eighth example of the detectorarray, optionally including one or more of the first through seventhexamples of the detector array, the plurality of adjustable imagingdetectors comprise at least two adjustable imaging detectors and at mosttwelve adjustable imaging detectors. In a ninth example of the detectorarray, optionally including one or more of the first through eighthexamples of the detector array, each of the plurality of adjustableimaging detectors has a same configuration as each other adjustableimaging detector. In a tenth example of the detector array, optionallyincluding one or more of the first through ninth examples of thedetector array, each detector unit comprises a pair of proximitydetectors disposed opposite to one another, a first one of the pair ofproximity detectors comprises a first optical sensor configured toproject a light-emitting diode (LED) beam, a second one of the pair ofproximity detectors comprises a second optical sensor configured toreceive the LED beam, and upon interruption of the LED beam by aninterfering object, the detector unit is configured to retract and/orpivot away from the interfering object. In an eleventh example of thedetector array, optionally including one or more of the first throughtenth examples of the detector array, each of the pair of proximitydetectors comprises a sliding-end contact sensor, and upon applicationof a threshold pressure to any sliding-end contact sensor by theinterfering object, the LED beam is interrupted. In a twelfth example ofthe detector array, optionally including one or more of the firstthrough eleventh examples of the detector array, each detector unitcomprises an exchangeable collimator, the exchangeable collimatorselected for a particular imaging application.

In another embodiment, a medical imaging system comprises an annulargantry circumscribing a cylindrical aperture, the annular gantryconfigured to rotate about a central axis tracing a length of thecylindrical aperture, a detector array positioned on the annular gantry,the detector array comprising a plurality of detector units extendingtoward the central axis of the cylindrical aperture, each of theplurality of detector units comprising a plurality of rows of cadmiumzinc telluride modules registered with an exchangeable collimator forreceiving incoming radiation from a subject positioned within thecylindrical aperture, and a processing unit configured with instructionsin non-transitory memory that when executed cause the processing unit tocoordinate the plurality of detector units to move to a first positionto receive the incoming radiation from the subject, and acquire medicalimaging data from the plurality of detector units based on the incomingradiation. In a first example of the medical imaging system, theprocessing unit is further configured to perform an automatic bodycontouring routine to estimate an outer perimeter of the subject, andcoordinating the plurality of detector units comprises translating andpivoting the plurality of detector units toward the estimated outerperimeter. In a second example of the medical imaging system, optionallyincluding the first example of the medical imaging system, each of theplurality of detector units comprises a plurality of proximity detectorsconfigured to, upon detecting the subject within a threshold distance ofa corresponding detector unit, retract the corresponding detector unitfrom the subject. In a third example of the medical imaging system,optionally including one or more of the first and second examples of themedical imaging system, the processing unit is further configured todetermine an angular resolution of the imaging data, and responsive toan insufficient angular resolution being determined, retract and/orpivot the plurality of detector units away from the subject, rotate theannular gantry about the central axis by a resolution angle, coordinatethe plurality of detector units to move to a second position to receivefurther incoming radiation from the subject, and acquire further imagingdata from the plurality of detector units based on the further incomingradiation.

In yet another embodiment, a method comprises positioning a subjectwithin a cylindrical aperture of an annular gantry, the annular gantryconfigured with a plurality of imaging detectors comprising respectivedetector units, each detector unit comprising an exchangeable collimatorpositioned adjacent to three rows of cadmium zinc telluride (CZT)modules, where each exchangeable collimator is configured to receive andnarrow incoming radiation from an area within the subject for eachcorresponding CZT module, translating and pivoting the plurality ofimaging detectors toward the estimated outer perimeter, acquiringnuclear medicine (NM) imaging data based on the incoming radiation, anddiagnosing a medical issue afflicting the area within the subject basedon the NM imaging data. In a first example of the method, each detectorunit comprises a pair of optical sensors projecting a light-emittingdiode (LED) beam therebetween, and the method comprises, responsive toany LED beam being obstructed by the subject, translating acorresponding detector unit away from the subject until the LED beam isunobstructed. In a second example of the method, optionally includingthe first example of the method, each detector unit comprises a pair ofsliding-end contact sensors respectively coupled to the pair of opticalsensors, and the method comprises, responsive to any LED beam beingbroken as a result of one of a corresponding pair of sliding-end contactsensors being contacted by the subject, pivoting a correspondingdetector unit away from the subject until the one of the correspondingpair of sliding-end contact sensors returns to a default position.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralof said elements or steps, unless such exclusion is explicitly stated.Furthermore, references to “one embodiment” of the present invention arenot intended to be interpreted as excluding the existence of additionalembodiments that also incorporate the recited features. Moreover, unlessexplicitly stated to the contrary, embodiments “comprising,”“including,” or “having” an element or a plurality of elements having aparticular property may include additional such elements not having thatproperty. The terms “including” and “in which” are used as theplain-language equivalents of the respective terms “comprising” and“wherein.” Moreover, the terms “first,” “second,” and “third,” etc. areused merely as labels, and are not intended to impose numericalrequirements or a particular positional order on their objects.

This written description uses examples to disclose the invention,including the best mode, and also to enable a person of ordinary skillin the relevant art to practice the invention, including making andusing any devices or systems and performing any incorporated methods.The patentable scope of the invention is defined by the claims, and mayinclude other examples that occur to those of ordinary skill in the art.Such other examples are intended to be within the scope of the claims ifthey have structural elements that do not differ from the literallanguage of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal languages ofthe claims.

The invention claimed is:
 1. A detector array, comprising: a pluralityof adjustable imaging detectors, each of the plurality of adjustableimaging detectors comprising a detector unit, each detector unit havinga plurality of rows of detector modules and a pair of proximitydetectors disposed opposite to one another and configured to project alight-emitting diode (LED) beam therebetween, wherein the detector unitis configured to retract in response to interruption of the LED beamduring extension of the detector unit and reverse pivot in response tointerruption of the LED beam while pivoting the detector unit, whereinthe plurality of adjustable imaging detectors are arranged on an annulargantry, the annular gantry configured for rotation about a first axis ofa cylindrical aperture of the annular gantry, the first axis extending alength of the cylindrical aperture, and wherein each of the plurality ofadjustable imaging detectors is disposed within the cylindrical apertureand extends orthogonally toward the first axis.
 2. The detector array ofclaim 1, wherein the plurality of adjustable imaging detectors areaffixed to an inner surface of the annular gantry, and wherein the firsttype of sensor is an optical sensor and the second type of sensor is acontact sensor.
 3. The detector array of claim 1, wherein the annulargantry comprises a track circumscribed by an inner surface of theannular gantry, and the plurality of adjustable imaging detectors arepositioned partially within the track such that each of the plurality ofadjustable imaging detectors is operable to move independently along thetrack with respect to each other adjustable imaging detector.
 4. Thedetector array of claim 1, wherein each of the plurality of adjustableimaging detectors comprises a telescoping detector carrier, where eachdetector unit is respectively positioned at an end of each telescopingdetector carrier nearest the first axis and each telescoping detectorcarrier is configured to extend toward or retract from the first axis.5. The detector array of claim 1, wherein the first axis is located at acenter of the cylindrical aperture, and the annular gantry is configuredfor full rotation about the first axis.
 6. The detector array of claim1, wherein each detector unit is configured to pivot about a second axisup to 60° from a default configuration, where each second axis isrespectively located at a center of each detector unit and each secondaxis is parallel with the first axis.
 7. The detector array of claim 1,wherein each detector module is a cadmium zinc telluride module.
 8. Thedetector array of claim 1, wherein each detector unit comprises threerows of detector modules, and each of the three rows of detector modulescomprises at least six detector modules.
 9. The detector array of claim1, wherein: a first one of the pair of proximity detectors comprises afirst optical sensor configured to project the LED beam across a cavityformed between the pair of proximity detectors and a second one of thepair of proximity detectors comprises a second optical sensor configuredto receive the LED beam.
 10. The detector array of claim 1, wherein eachof the plurality of adjustable imaging detectors has a sameconfiguration as each other adjustable imaging detector.
 11. Thedetector array of claim 1, wherein: each of the pair of proximitydetectors extends from a surface of the detector unit; a first one ofthe pair of proximity detectors comprises a first optical sensorconfigured to project the LED beam across a cavity formed between thepair of proximity detectors and a second one of the pair of proximitydetectors comprises a second optical sensor configured to receive theLED beam; interruption of the LED beam during extension of the detectorunit comprises interruption of the LED beam by an interfering objectwithin the cavity; and in response to interruption of the LED beam bythe interfering object within the cavity, the detector unit is furtherconfigured to retract until the LED beam is unobstructed.
 12. Thedetector array of claim 11, wherein: each of the pair of proximitydetectors is configured to be depressed toward the surface of thedetector unit in response to application of a threshold pressure;interruption of the LED beam while pivoting comprises application of thethreshold pressure to the first one of the pair of proximity detectorsor the second one of the pair of proximity detectors by the interferingobject; and in response to the LED beam being interrupted by theapplication of the threshold pressure to the first one of the pair ofproximity detectors or the second one of the pair of proximitydetectors, the detector unit is further configured to pivot away fromthe interfering object until the LED beam is unobstructed.
 13. Thedetector array of claim 1, wherein each detector unit comprises anexchangeable collimator, the exchangeable collimator selected for aparticular imaging application.
 14. The detector array of claim 1,wherein: each of the pair of proximity detectors is configured to beadjusted from a default, non-depressed position that extends from asurface of the detector unit and a depressed position that does notextend from the surface of the detector unit when the detector unit ispivoted toward and contacts an interfering object; a first one of thepair of proximity detectors comprises a first optical sensor configuredto project the LED beam across a cavity formed between the pair ofproximity detectors in the default, non-depressed position; a second oneof the pair of proximity detectors comprises a second optical sensorconfigured to receive the LED beam; the LED beam is interrupted inresponse to the first one of the pair of proximity detectors or thesecond one of the pair of proximity detectors being adjusted to thedepressed position; and in response to interruption of the LED beamwhile pivoting, the detector unit is further configured to pivot awayfrom the interfering object until the first one of the pair of proximitydetectors or the second one of the pair of proximity detectors returnsto the default, non-depressed position.